/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.example.android.nfc.record;

import java.util.Arrays;
import java.util.NoSuchElementException;

import android.app.Activity;
import android.nfc.FormatException;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.LinearLayout;

import com.example.android.nfc.NdefMessageParser;
import com.google.common.base.Charsets;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Iterables;
import com.kpu.R;

/**
 * A representation of an NFC Forum "Smart Poster".
 */
public class SmartPoster implements ParsedNdefRecord {

	/**
	 * NFC Forum Smart Poster Record Type Definition section 3.2.1.
	 * 
	 * "The Title record for the service (there can be many of these in
	 * different languages, but a language MUST NOT be repeated). This record is
	 * optional."
	 */
	private final TextRecord mTitleRecord;

	/**
	 * NFC Forum Smart Poster Record Type Definition section 3.2.1.
	 * 
	 * "The URI record. This is the core of the Smart Poster, and all other
	 * records are just metadata about this record. There MUST be one URI record
	 * and there MUST NOT be more than one."
	 */
	private final UriRecord mUriRecord;

	/**
	 * NFC Forum Smart Poster Record Type Definition section 3.2.1.
	 * 
	 * "The Action record. This record describes how the service should be
	 * treated. For example, the action may indicate that the device should save
	 * the URI as a bookmark or open a browser. The Action record is optional.
	 * If it does not exist, the device may decide what to do with the service.
	 * If the action record exists, it should be treated as a strong suggestion;
	 * the UI designer may ignore it, but doing so will induce a different user
	 * experience from device to device."
	 */
	private final RecommendedAction mAction;

	/**
	 * NFC Forum Smart Poster Record Type Definition section 3.2.1.
	 * 
	 * "The Type record. If the URI references an external entity (e.g., via a
	 * URL), the Type record may be used to declare the MIME type of the entity.
	 * This can be used to tell the mobile device what kind of an object it can
	 * expect before it opens the connection. The Type record is optional."
	 */
	private final String mType;

	private SmartPoster(UriRecord uri, TextRecord title,
			RecommendedAction action, String type) {
		mUriRecord = Preconditions.checkNotNull(uri);
		mTitleRecord = title;
		mAction = Preconditions.checkNotNull(action);
		mType = type;
	}

	public UriRecord getUriRecord() {
		return mUriRecord;
	}

	/**
	 * Returns the title of the smart poster. This may be {@code null}.
	 */
	public TextRecord getTitle() {
		return mTitleRecord;
	}

	public static SmartPoster parse(NdefRecord record) {
		Preconditions
				.checkArgument(record.getTnf() == NdefRecord.TNF_WELL_KNOWN);
		Preconditions.checkArgument(Arrays.equals(record.getType(),
				NdefRecord.RTD_SMART_POSTER));
		try {
			NdefMessage subRecords = new NdefMessage(record.getPayload());
			return parse(subRecords.getRecords());
		} catch (FormatException e) {
			throw new IllegalArgumentException(e);
		}
	}

	public static SmartPoster parse(NdefRecord[] recordsRaw) {
		try {
			Iterable<ParsedNdefRecord> records = NdefMessageParser
					.getRecords(recordsRaw);
			UriRecord uri = Iterables.getOnlyElement(Iterables.filter(records,
					UriRecord.class));
			TextRecord title = getFirstIfExists(records, TextRecord.class);
			RecommendedAction action = parseRecommendedAction(recordsRaw);
			String type = parseType(recordsRaw);
			return new SmartPoster(uri, title, action, type);
		} catch (NoSuchElementException e) {
			throw new IllegalArgumentException(e);
		}
	}

	public static boolean isPoster(NdefRecord record) {
		try {
			parse(record);
			return true;
		} catch (IllegalArgumentException e) {
			return false;
		}
	}

	public View getView(Activity activity, LayoutInflater inflater,
			ViewGroup parent, int offset) {
		if (mTitleRecord != null) {
			// Build a container to hold the title and the URI
			LinearLayout container = new LinearLayout(activity);
			container.setOrientation(LinearLayout.VERTICAL);
			container.setLayoutParams(new LayoutParams(
					LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
			container.addView(mTitleRecord.getView(activity, inflater,
					container, offset));
			inflater.inflate(R.layout.tts, container);
			container.addView(mUriRecord.getView(activity, inflater, container,
					offset));
			return container;
		} else {
			// Just a URI, return a view for it directly
			return mUriRecord.getView(activity, inflater, parent, offset);
		}
	}

	/**
	 * Returns the first element of {@code elements} which is an instance of
	 * {@code type}, or {@code null} if no such element exists.
	 */
	private static <T> T getFirstIfExists(Iterable<?> elements, Class<T> type) {
		Iterable<T> filtered = Iterables.filter(elements, type);
		T instance = null;
		if (!Iterables.isEmpty(filtered)) {
			instance = Iterables.get(filtered, 0);
		}
		return instance;
	}

	private enum RecommendedAction {
		UNKNOWN((byte) -1), DO_ACTION((byte) 0), SAVE_FOR_LATER((byte) 1), OPEN_FOR_EDITING(
				(byte) 2);

		private static final ImmutableMap<Byte, RecommendedAction> LOOKUP;
		static {
			ImmutableMap.Builder<Byte, RecommendedAction> builder = ImmutableMap
					.builder();
			for (RecommendedAction action : RecommendedAction.values()) {
				builder.put(action.getByte(), action);
			}
			LOOKUP = builder.build();
		}

		private final byte mAction;

		private RecommendedAction(byte val) {
			this.mAction = val;
		}

		private byte getByte() {
			return mAction;
		}
	}

	private static NdefRecord getByType(byte[] type, NdefRecord[] records) {
		for (NdefRecord record : records) {
			if (Arrays.equals(type, record.getType())) {
				return record;
			}
		}
		return null;
	}

	private static final byte[] ACTION_RECORD_TYPE = new byte[] { 'a', 'c', 't' };

	private static RecommendedAction parseRecommendedAction(NdefRecord[] records) {
		NdefRecord record = getByType(ACTION_RECORD_TYPE, records);
		if (record == null) {
			return RecommendedAction.UNKNOWN;
		}
		byte action = record.getPayload()[0];
		if (RecommendedAction.LOOKUP.containsKey(action)) {
			return RecommendedAction.LOOKUP.get(action);
		}
		return RecommendedAction.UNKNOWN;
	}

	private static final byte[] TYPE_TYPE = new byte[] { 't' };

	private static String parseType(NdefRecord[] records) {
		NdefRecord type = getByType(TYPE_TYPE, records);
		if (type == null) {
			return null;
		}
		return new String(type.getPayload(), Charsets.UTF_8);
	}
}
